1. Field of the Invention
The present invention relates to resource allocation between cluster heads in a wireless network environment, and more particularly, to a method of eliminating collision between clusters by dividing a whole network into a plurality of clusters and then allowing each of the clusters to separately perform resource allocation.
2. Description of the Related Art
In a wireless ad-hoc network, each of a plurality of mobile nodes independently performs communication in a multi-hop manner by sharing a medium according to a peer-to-peer service. Since many nodes share the medium in such a wireless ad-hoc network, if each node is not controlled in terms of accessing the medium, collision occurs between the nodes. In particular, if a node has a limit in terms of a consumable energy source, an energy loss caused by the collision consumes a large portion of the consumable energy source. In order to control the collision, it is necessary to allocate a time slot to the node by using link information between neighboring nodes.
However, in the wireless ad-hoc network, a certain node only recognizes its neighboring nodes, and thus, it is necessary for one node to collect all of the pieces of link information in the wireless ad-hoc network so as to allocate a resource to the certain node without collision. The one node allocates resources to the nodes by using all the pieces of link information, and broadcasts a result of the allocation to the wireless ad-hoc network, so that the nodes can communicate without collision.
Since the one node has all the pieces of link information, the aforementioned resource allocation method can consider every possible collision in the wireless ad-hoc network. However, as the scale of the wireless ad-hoc network increases, the amount of calculations to be performed by the one node conducting an algorithm sharply increases. Considering that one of the most important issues in the wireless ad-hoc network is a low power issue, the increase of the calculation amount may be a demerit. Also, in general, it is assumed that the nodes are dynamically mobile in the wireless ad-hoc network, meaning that any node from among the nodes may leave the wireless ad-hoc network, and an arbitrary new node may enter the wireless ad-hoc network anytime. In this case, since link information between the nodes is changed, it is necessary to renew resource allocation for communication without collision. Thus, the resource allocation renewal with respect to an increase of node mobility is a serious demerit in the wireless ad-hoc network.
Although a centralized resource allocation algorithm according to the prior art works without a problem, there may be a situation in which not every neighboring node can be actually treated as one network. For example, although a service provider establishes its network and allocates resources to nodes so as to avoid collision between the nodes in the network, if another service provider establishes another network adjacent to the network, the network and the other network cannot be regarded as one network such that collision between the network and the other network may not be controlled.